Treatment of pulp articles and material therefor



0R 1,857,498 EX /\/a 2 3 i Mefw/ 0 x14? Patented May 10, 1932 ALBERT L. CLAPP, OF DANVERS, MASSACHUSETTS TREATMENT OF PULP ARTICLES AND MATERIAL THEREFOR No Drawing. Application filed September 27, 1923. Serial No. 808,881.

This invention relates to the treatment of silicate, the sodium silicate thus being abfibrous articles such as those made frowllg sorbed not only by the pulp fibers but also by Wand has for its object to impro' the fine particles of infusoria-l earth which e c aracteristics of articles such as bottles, fill the pores and interstices of the article, so dishes, toys and flower pots, especialmfl that when the articles is dried or set, it is mfild'dfiom t e p p much stiffer, stronger, and far more resistant Iii moulding articles from cellulose pulp, it to the action of moisture than before. A furis found that the article is likely to be weak ther advantage of using a composition of this and susceptible to damage even after drying, character is that metallic oxide pigments, such particularly when a free pulp st0ckfor inas ferric oxide, chrome oggide, nigkel gxide, stance ground wood pulpis employed as a zinc 0x1 d e, and.tlie like may be incorporated raw material. Some moulding processes reinto the composition if a colored product is quire the use of a free pulp containing little, desired, and the pigment firmly fixed to the if any, sizing or filling materials, and in such fibers of the articles, sodium silicate apparcases the finished articles are likely to be quite ently reacting with the oxide to form a siliflexible and weak, so that considerable loss is cate, particularly when the articles are dried sustained through damage in handling, and at elevated temperatures, say, 200 to 3091b their useful life is quite short, especially when which temperatures are insufiici'fitly'high to exposed to moisture, as under these condidecompose or char the cellulose pulp of which tions they become soft and punky, and finally the articles are composed. When articles so disintegrate. pigmented are soaked in water, it is found Examiner I have found that such articles may be that the pigment is not washed out, even after treated with a composition capable of penedays of immersion indicating that a substantrating the pores and interstices of the artitially permanent fixation of the pigment on cle, and that such a composition, especially the fibers has been effected. Apparently also, when containing ingredients which will react there is some slowareaction,hetwem the while in the article, may impart thereto dedium silicate and thekieselguhrr sirable qualities which are lacking in the lfp'ia'ctisin g the treatment of the present untreated articles. Thus, a liquid containing invention, it is preferable to use moulded artiin suspension therein fine particles with which cles which are free from sizing materials so certain ingredients of the liquid may react, as to permit rapid and uniform impregnation may be used, the liquid carrying the partiof the articles with the composition. Comcles into the pores and interstices, where the positions made up of various strengths of reaction between them may take place, wheresodium silicate solution and containing vaupon the articles may be allowed to set. For rious amounts of kieselguhr and/or pigment example, if such articles are treated with a may be used, one satisfactory composition, com ositign comprising a sol utiqnp f sodium for example, being made of 10 to 15 Baum silica containinglifiiep articles of infusoifial sodium silicate containing about 1% kieseleartlfiir'cellite in sus i fiifiiimithcnir d guhr and about 2% pigment uniformly susthmmsfisa-"an strengthened considpended therein. The sodium silicate emera-bly, and are rendered much more waterployed as a raw material is preferably one resistant. Apparently, the infusorial earth, containing a comparativel low free Na O which is capable of taking 11 four times its content and a high free Si 2 content, as this weight in water passes into t e pores and inmaterial apparently sets more rapidly to give terstices of the articles along with theiodium' a more waterproof product than when sodium silicate of high free Na O content and low free SiO content is used. The moulded pulp articles when dipped into the composition is readily impregnated throughout, and when subsequentl dried or set, say at 200 to 300 F., are sti and suiiiciently strong to withstand shocks without breaking. They are also sufliciently water-resistant to withstand a long period of immersion in water without disintegrating.

lVhile the example given deals with a composition in which kieselguhr is present to increase the stiflness, strength, and water resistance of the product, the articles may be treated to less advantage with sodium silicate containing only the pigment in suspension. It is necessary, however, that the article be treated with the kieselguhr and/0r pigment in suspension in the sodium silicate solution, for under these conditions the materials in finely divided condition are carried into the pores and I interstices of the article, the pigment being fixed while setting of the composition takes lace. The same results cannot be obtained y first treating the articles with sodium silicate solution, and then treating with an aqueous suspension of the kieselguhr and/or the pigment, or vice versa, as in such case the suspended particles are not carried into the articles as satisfactorily, and the water of the suspension tends to dilute the water of the sodium silicate solution.

Having thus described a certain embodiment of this invention, it should be evident to those skilled in the art that various changes and modifications might be made therein without departing from the spirit or scope of invention as defined by the appended claims.

I claim:

1. A method which comprises impregnating throughout pre-moulded cellulose pulp articles with a sodium silicate solution containing kieselguhr in suspension therein, and heat-dryingthe articles at temperatures insufficiently high to decompose the pulp.

2. A method which comprises impregnating throughout pre-moulded cellulose pulp articles with a sodium silicate solution containing a metallic oxide pigment in suspension therein, and heat-drying the articles at temperatures insufliciently high to decompose the pulp.

3. A method which comprises inpregnating throughout pre-moulded cellulose pulp articles with a sodium silicate solution containing kieselguhr and a metallic oxide pigment in suspension therein, and heat-drying the articles at temperatures insufliciently high to decompose the pulp.

4. A method which comprises impregnating throughout pre-moulded cellulose pulp articles with a sodium silicate solution containing kieselguhr and a metallic oxide pigment in suspension therein, and drying the articles at about 200 to 300 F.

signature.

ALBERT L. CLAPP. 

